C-Reactive Protein (CRP)
How It Feels
The blood sample is taken from a vein in
your arm. An elastic band is wrapped around your upper arm. It may feel tight.
You may feel nothing at all from the needle, or you may feel a quick sting or
There is very little chance of a problem from
having a blood sample taken from a vein.
- You may get a small bruise at the site. You can
lower the chance of bruising by keeping pressure on the site for several
- In rare cases, the vein may become swollen after the blood
sample is taken. This problem is called phlebitis. A warm compress can be used
several times a day to treat this.
- Ongoing bleeding can be a
problem for people with bleeding disorders. Aspirin, warfarin (such as
Coumadin), and other blood-thinning medicines can make bleeding more likely. If
you have bleeding or clotting problems, or if you take blood-thinning medicine,
tell your doctor before your blood sample is taken.
A C-reactive protein (CRP) test is a
blood test that measures the amount of a
protein called C-reactive protein in your
The normal values listed here—called a reference range—are just a guide. These ranges vary from lab to lab, and your lab may have a different range for what's normal. Your lab report should contain the range your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab.
Results are usually available within 24 hours.
Any condition that results in sudden or severe
inflammation may increase your CRP levels.
Some medicines may
decrease your CRP levels.
Many conditions can change CRP
levels. Your doctor will talk with you about any abnormal results that may be
related to your symptoms and past health.
High-sensitivity C-reactive protein (hs-CRP) levels
High-sensitivity C-reactive protein (hs-CRP) measures very low
amounts of CRP in the blood. This test may help find your risk of heart problems, especially when it is considered along with other risk factors such as cholesterol, age, blood pressure, and smoking. It may be done to
find out if you have an increased chance of having a sudden heart problem, such
heart attack. But the connection between high CRP
levels and heart disease risk is not understood very well.
High-sensitivity C-reactive protein (hs-CRP) level1
Less than 0.1
mg/dL or less than 1 mg/L
hs-CRP level and heart disease risk2
Less than 1.0 mg/L
1.0 to 3.0 mg/L
More than 3.0 mg/L